A contactor is the major electrical component in an electric vehicle supply equipment or EVSE. Due to possible mechanical failure of the contactor and/or the electrical control circuit problem, especially under EMI, ESD, and other severe conditions, the contactor could potentially be stuck open or stuck close. When stuck open, the electric vehicle or EV will not be charged as commanded, when stuck close, current will be continuously provided to the EV unexpectedly, which could present a safety hazzard to the user.
What is needed is a means to monitor the contactor and ensure reliable indications of the proper functioning of the contactor. Further, what is needed is a implementable method to constantly monitor the state of the contactor.